package com.zx.util;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;
import javax.imageio.ImageIO;

/**
 * @version v1.0
 * @Project: managing-self
 * @Title: VerificationUtil
 * @Description: 验证码工具类
 * @author: zhangxue
 * @date: 2019年10月4日下午9:54:15
 * @company: 未知
 * @Copyright: Copyright (c) 2015
 */
public class VerificationUtil {

    // 给定范围获得随机颜色;
    private static Color getRandColor(int fc, int bc) {
        Random random = new Random();
        if (fc > 255) {
            fc = 255;
        }
        if (bc > 255) {
            bc = 255;
        }
        int r = fc + random.nextInt(bc - fc);
        int g = fc + random.nextInt(bc - fc);
        int b = fc + random.nextInt(bc - fc);
        return new Color(r, g, b);
    }

    public static String getVerificationCode(OutputStream outputStream) throws IOException {
        // 在内存中创建图象
        int width = 70, height = 35;
        BufferedImage image = new BufferedImage(width, height,
                BufferedImage.TYPE_INT_RGB);

        // 获取图形上下文
        Graphics g = image.getGraphics();

        // 生成随机类
        Random random = new Random();

        // 设定背景色
        g.setColor(getRandColor(200, 255));
        g.fillRect(0, 0, width, height);

        // 设定字体
        g.setFont(new Font("微软雅黑", Font.PLAIN, 23));

        // 画边框
        g.setColor(getRandColor(150, 200));
        g.drawRect(0, 0, width - 1, height - 1);

        // 随机产生20条干扰线，使图象中的认证码不易被其它程序探测到

		/*for (int i = 0; i < 30; i++) {
			g.setColor(getRandColor(100, 170));
			int x = random.nextInt(width);
			int y = random.nextInt(height);
			int xl = random.nextInt(200);
			int yl = random.nextInt(200);
			g.drawLine(x, y, x + xl, y + yl);
		}*/

        // 取随机产生的认证码(4位数字)
        String sRand = "";
        for (int i = 0; i < 4; i++) {
            String rand = "" + (char) (random.nextInt(26) + 65);

            sRand += rand;
            // 将认证码显示到图象中
            g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));
            // 调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
            g.drawString(rand, 15 * i + 5, 27);
//			g.drawString(rand, 10 * i + 8, 26);
        }
        // 图象生效
        g.dispose();

        // 将图片写入输出流中
        ImageIO.write(image, "JPEG", outputStream);

        return sRand;
    }
}
